Hard to Digest Foods: Are You Ready for Some Surprises?

Hard to digest foods, worst foods for digestion: woman holding stomach in digestive pain

Hard to Digest Foods: Are You Ready for Some Surprises?

By: Julie Mancuso, founder of JM Nutrition, registered dietitians and nutritionists at JM Nutrition, Sarah Jabeen, MD. Learn more about our team

In this post:

  • list of hard to digest foods 

  • the underlying reasons why these foods are hard to digest


Some foods are hard to digest, pure and simple.

It’s also a fact that most of us experience some form of digestive problem at one point or another, no matter how robust the digestive system. For many of us, the digestive distress is often caused by the foods we eat. Some of these are well-known while others will surprise.

Related: Gut Health 101


My personal struggle with digestive health and hard to digest foods

Reducing digestive distress is naturally important to me professionally, but also personally because I’ve been struggling with all sorts of gastro-intestinal problems the better part of my adult life.

In fact, it was the primary reason why I decided on a career in nutritional counselling over fifteen years ago. 

In all honesty, I still find food digestion challenging at times, but it sure has gotten better since I improved my own eating habits. 

I’ve learned a great deal about digestion from extensive research, personal experience, countless consultations with medical practitioners and the experience of my clients.

What’s more, I’ve learned a great deal about what foods are hard to digest and which are more benign. To this day, I always choose what I eat based on the effect it has on my digestive system. 

Poor digestion can no doubt lead to frustration. Sometimes determining the root cause of digestive problems takes time, a great deal of time. Besides, the grumbling, churning and general discomfort makes it hard to enjoy life, especially food. 


Some hard to digest foods are commonly known, while others are not

To alleviate digestive distress, start with food first.

We all know that if we consume large amounts of fatty, greasy, fried, salty or sweet foods, we are likely to trigger some form of digestive discomfort. This can range from slight churning in some to debilitating cramps and pain in others.

But other, less obvious hard to digest foods exist. These foods can also greatly upset the digestive system, causing rumbling, gas and pain.


Hard to Digest Foods


Raw Onions

Raw onions can be hard to digest, for some.

Onions can cause a good deal more than just leaving you with that pungent onion-breath. Some people pass gas and feel digestive discomfort after eating onions in their raw form, while others burp and bloat.

Why are onions hard to digest?

Onions are hard to digest largely because they contain fructans, which are not absorbed well in the small intestine. In fact, as fructans ferment, they can cause a great deal of digestive distress in the form of bloating, gas and diarrhea.

I recommend avoiding raw onions if your digestive system is sensitive.

Which foods contain fructans?

  • onions & shallots, as mentioned
  • garlic 
  • some cereals & grains (wheat, rye, barley, etc.)
  • savoy cabbage
  • artichokes
  • leeks
  • fennel
  • Brussels sprouts
  • asparagus
  • ripe bananas
  • watermelon
  • dried fruit
  • pistachios
  • chicory root
  • and others


Tips to reduce the digestive upset of onions

If you’re just not prepared to give up eating raw onions and must have them on your burger or sandwich, reduce the portion. If the symptoms are reduced or go away altogether, you know you found the cause. 

Another way to reduce the severity of the mentioned symptoms is to cook the onions.

Furthermore, you can take digestive enzymes to help to alleviate some of these gastrointestinal disturbances caused by raw onions. 

When considering taking supplements, it is always a good idea to seek the help of a qualified practitioner who can help you select the right digestive enzymes. Please don’t take it upon yourself to do so.


Raw fruits and vegetables

And you thought all fruits and vegetables were good for you…

Well, they no doubt are, for a number of reasons.

Some people, however, experience gastrointestinal problems when digesting certain fruits and vegetables. This fact is often omitted from lists of hard to digest foods.

Fruits and vegetables, however, may upset digestion.

Why are some fruits and vegetables hard to digest?

Some fruits and vegetables contain an insoluble fibre—a fibre that does not dissolve in water. While such fibre has the benefit of passing through a person’s system rather quickly, taking other foods with it, and thereby helping to clean out your system, it can also irritate the walls of your colon in the process. This can cause discomfort and even pain.

Therefore, limit eating some vegetables (more on that later) and the skins of fruits and vegetables because they can be harder to digest.

Again, the best way to tell if these are responsible for your digestive problems is to keep a food log where you note the eaten foods and how they make you feel shortly consumption. Do so for at least a week and try to identify a pattern.

If you find that your digestive system reacts well to fruits and vegetables, then move on to the next food item on the list.

To learn more about the difference between raw and cooked vegetables, take a look at the interview from JM Nutrition’s own Registered Dietitian, Lyndsay Hall: Raw vs. Cooked: How to Get the Most Out of Your Vegetables


Cabbage and cruciferous vegetables

Cruciferous vegetables are one of those potentially hard to digest foods, at least for some. 

But don’t eliminate them from your diet just yet. Reason being, cruciferous vegetables such as cabbage, broccoli and cauliflower have a number of important nutrients needed by humans.

Why is cabbage hard to digest?

That said, however, cabbage and cruciferous vegetables contain indigestible sugars. When these sugars are digested, some people experience gas, flatulence, belching and abdominal discomfort.

Consume in small quantities, if you suspect cruciferous vegetables aggravate the symptoms.

Keep in mind that cooked cruciferous vegetables are much easier on the digestive system. If cooking does little to avert the mentioned aches and pains, eliminate them altogether to see if you feel the difference.

Discover more about cruciferous vegetables and digestion.



Corn contains a good deal of the necessary, healthy fibre, which we all need to promote digestive movement and to keep us full for longer. That’s a good thing.

Why is corn hard to digest?

Corn, however, has another type of fibre called cellulose—something humans have a difficult time breaking down. The end result: abdominal pain and gas.

If you’re going to consume corn, chew thoroughly to help digestion.

Related: Registered dietitians for digestive health support



For some time now dairy has found its way onto many lists of the worst foods for digestion.

It’s important to remember that dairy doesn’t adversely affect all people, only some. It also affects people in varying degrees, so it may be hard to digest for you, but not your loved one.

Furthermore, dairy contains lactose, which is not easily broken down by the digestive system.

As you no doubt know, some people have a complete intolerance to lactose and can become seriously ill upon its consumption. The rest of us, on the other hand, may just experience some gas and bloating, the intensity and frequency of which varies from person to person.

Some people who reduce their dairy intake, experience immediate improvement in this area.

Pay heed to how you feel immediately after ingesting any dairy product.

Keep a food log that lists how you feel after certain foods are eaten to help you to identify a potential pattern. This applies to any ingested food, not just dairy.

Once you recognize a pattern, limit the food or eliminate it altogether, if need be.

Alternatively, you can contact our dietitian and nutritionist for lactose intolerance.

What’s better for digestion: goat milk vs. cow milk?

Goat dairy is generally easier to digest because it contains lower levels of a protein called alphaS1-casein than cow’s dairy.

In addition, the fat globules in goat’s milk are much smaller than those of cow’s, further aiding in digestion.

Learn more about the differences between cow and goat milk.


Spicy foods

There’s a reason why for centuries the Europeans coveted spices like precious stones. Without them, food is bland and, in some cases, barely edible. Used by all cultures, spices are so great in number that most of us aren’t even familiar with many of them.

Spices, however, may impact more than just the flavour of your food. While some people don’t seem to be negatively affected upon the ingestion of spices, others are not as lucky and find them hard to digest.

The matter is complicated even further by the fact that some people are only affected by certain spices, and not others. You’ll have to gauge this yourself by keeping a close eye on how your own body reacts.

Why are spices hard to digest?

The fact is that spices are known to irritate the lining of the esophagus. Potentially, this could lead to discomfort. If you suspect spices are an irritant, consume in small amounts. 



A sugar-alcohol, sorbitol is an artificial sweetener often found in sugar-free gum and a number of other sweets.

Sorbitol takes a long time to digest and may cause gas build up as a result, particularly in those who are prone to various digestive conditions.

In addition, chewing gum itself can cause you to swallow a large amount of air. This leads to trapped gas and possible discomfort or even pain, making the problem worse.

Read more about Sorbitol and its link to gastrointestinal complaints.


Acidic foods

In short, foods such as tomatoes, oranges and lemons have been found to increase acid reflux. As such, put a limit on their consumption, if you have digestive troubles.

Here’s how you can relieve acid reflux, according to Harvard Health. Alternatively, seek the help of a dietitian for acid reflux diet plan.


Processed foods

Processed foods are packaged foods that are not in their natural form. These foods are often loaded with additives, preservatives and other chemicals.

They also contain sodium, and frequently, white flour. Most of these foods lack the necessary fibre for proper digestion, and subsequently cause constipation. This makes them one of the worst foods for digestion.

Prepare foods from scratch and eat them in their most natural form instead. Doing so is not only better for digestion, but also for your health in general.



We’ve all heard the old saying that beans are hard to digest and cause flatulence. Although we need to dismiss many of the nutrition old wives’ tales as they are simply outdated and have since been proven to be misconceptions, this one is largely true.

Why are beans hard to digest?

Beans contain a complex sugar called oligosaccharide that humans cannot digest without the help of digestive enzymes. 

Despite the fact that they are abundant in fibre and high in protein, which are both essential for a healthy diet, the mentioned sugar can cause digestive upset. When it enters the digestive system, it creates gas and potential discomfort.

That is not to say you should strike beans from your diet in their entirety, but consume sparingly if you’re hypersensitive.



It is not uncommon to hear people complain about bloating or a generally uneasy feeling after consuming lentils.

Lentils are a nutritional powerhouse. That is, they contain protein, fibre and healthy carbohydrates–not to mention the list of vitamins and minerals. 

So why do lentils cause bloating?

There are several reasons, but the primary one being high fibre content. Another is the presence of FODMAPs, which Hopkins Medicine defines as fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, which are short-chain carbohydrates (sugars) that the small intestine absorbs poorly.

Again, it’s important to be mindful when consuming lentils as they may be hard to digest. Observe, gauge and limit, if you find they cause digestive upset. 


Red Meat

For some, red meat may be one of those hard to digest foods.

Livestrong states that, “heme iron, which is found in red meats, and high levels of fat can all contribute to an increase in oxidative stress in the digestive system. Oxidative stress is an imbalance between free radical production and antioxidants and can result in inflammation and impairment of gut bacteria.”

This could certainly be a contributing factor to the indigestion that some people experience after eating red meat. An important point to note, however, is that red meat is also high in saturated fats that can further contribute to improper digestion.


Meats with casing

Meats such as sausages are wrapped in casing, which can be hard to digest for some. This is especially true if the casing is artificial rather than natural.

In addition, they are processed which, in and of itself, can be hard on digestion.

The combination of processing and the casing is a digestive double whammy. 


Citrus juices

Surprised to see citrus juices on the list of hard to digest foods? Most people are.

Citrus juices, however, can irritate the stomach and cause discomfort in people who are susceptible to acid reflux, often aggravating such symptoms. Pay close attention and see if juice is responsible.


Carbonated drinks

This one is not much of a surprise.

The vast majority of carbonated drinks aren’t good for overall health anyway. But being acidic in nature, carbonated drinks also distend the stomach, causing discomfort in some. Carbonation doesn’t help things either. Plain and simple. Avoid. 



In addition to the many adverse effects of regularly consuming alcohol in excessive amounts, certain alcoholic drinks such as beer have been known to trigger gas in some people—a fact that is not widely known by the general population.

Drinking alcohol can also inflame the lining of the stomach, preventing nutrients from being properly absorbed by your system.

What’s more, alcohol dehydrates the body. This lack of proper water intake in itself can lead to constipation, discomfort and pain. Unfortunately, the bottoms up can make your digestive system bottom out, so pay heed.

Related: Alcohol Selections For Weight Loss


Why is coffee hard to digest?

Coffee is inherently acidic, which means it can irritate our stomach and cause digestive distress, especially on an empty stomach.

Why coffee on an empty stomach is not a good idea?

If we drink coffee on an empty stomach, it can be hard to digest. This is because our body is in a “fasted” state when gastric secretions are already high awaiting our first meal of the day.

The IBS & Gut Health Clinic states that, “Black coffee can especially irritate your gut if you drink it on an empty stomach. It can reduce the acid your stomach will need for digestion later, which means that it can lead to abdominal pain, cramping, and bloating.”



Some people find gluten difficult to digest. This does not just apply to those stricken with Celiac disease. You may even have a mild sensitivity to it and not even know it. 

Breads, pastas and cereals are the usual suspects here. But there are some less obvious foods that can also contain a fair amount of gluten. Foods and drinks such as beer, certain sauces, dressings and processed foods can all carry gluten.

It’s important to keep in mind that not all people may experience troublesome symptoms after ingesting gluten, but consider reducing it, if plagued by ongoing digestive problems.

Related: Celiac Disease diet support



Soy falls under the broader category of legumes. Legumes can be difficult to digest, especially when consumed in large quantities or when intake is suddenly increased from the baseline that your body is used to.

In addition, The American Journal of Clinical Nutrition explains that, “Ingestion of soy products may cause excessive intestinal gas. This gas results from colonic bacterial fermentation of the indigestible oligosaccharides raffinose and stachyose, which are present in high concentrations in legumes.”

As a result, soy may be hard to digest, at least for some.



Hard To Digest Foods Take-Away

The list found here is by no means an exclusive one, but more of a sweeping guideline. Some of the foods listed are common knowledge, but the others not so much. And often, these are the foods that people tend to overlook when trying to pinpoint the causes of their digestive troubles.

If you’re a sufferer who’s looking for answers, I strongly encourage you to reduce or eliminate these foods. Look at the list, follow the suggestions, observe how you feel and discover for yourself. That’s the only sure way of knowing what affects you as an individual. 

As always, I encourage everyone to seek the help of a trained digestive health professional in the process to guide you along. Digestive problems can be overwhelming and exasperating—something with which I can certainly empathize, and as such, they require attention.

If you require personal counselling, contact us for an appointment or book a free consultation


Other Popular Posts:

Foods and Supplements For Stress Management

All About Metabolism

How To Save Money On Groceries

Nutrition Myths vs. Facts

Meal Prepping Tips & Strategies

All About Intermittent Fasting

How To Increase Energy Levels and Beat The Afternoon Slump

Pros And Cons Of Keto Diet


Our nutrition blog has been named one of the Top 100 Nutrition Blogs, Websites and Newsletters to Follow in 2020, 2021, 2022 & 2023 and one of the Top Canadian Nutrition Blogs by Feedspot. So don’t miss out and subscribe below to both the newsletter that includes latest blog posts. 

JM Nutrition’s practitioners assist clients from all walks of life with the management of various digestive conditions: Crohn’s & Colitis dietitian & nutritionist, IBS nutritionist, GERD dietitian, diverticulitis diet counselling, low-FODMAP diet counselling and more.

JM Nutrition is a nutritional counselling service by dietitians and nutritionists in Toronto, as well as other locations across Canada. We offer in-person appointments and the services of virtual nutritionists and dietitians

Author: Julie Mancuso

Julie Mancuso


Julie Mancuso is a graduate of the University of Toronto, founder and owner of JM Nutrition, a nutritional counselling service by registered dietitians and nutritionists. For 15+ years, JM Nutrition has helped thousands reach their health, wellness and nutrition goals. Julie and her team regularly lend their expertise to a variety of health publications such as Reader's Digest, Livestrong, Business Insider, Food Network, Today's Parent, MyFitnessPal, Toronto Star, Elle Magazine, Best Life, Weight Watchers and many more.